scholarly journals A therapeutic convection–enhanced macroencapsulation device for enhancing β cell viability and insulin secretion

2021 ◽  
Vol 118 (37) ◽  
pp. e2101258118
Author(s):  
Kisuk Yang ◽  
Eoin D. O’Cearbhaill ◽  
Sophie S. Liu ◽  
Angela Zhou ◽  
Girish D. Chitnis ◽  
...  
Keyword(s):  
Insulin Secretion ◽  
Cell Viability ◽  
Three Dimensional ◽  
Insulin Response ◽  
Convective Transport ◽  
Passive Diffusion ◽  
Loading Capacity ◽  
Nutrient Delivery

Islet transplantation for type 1 diabetes treatment has been limited by the need for lifelong immunosuppression regimens. This challenge has prompted the development of macroencapsulation devices (MEDs) to immunoprotect the transplanted islets. While promising, conventional MEDs are faced with insufficient transport of oxygen, glucose, and insulin because of the reliance on passive diffusion. Hence, these devices are constrained to two-dimensional, wafer-like geometries with limited loading capacity to maintain cells within a distance of passive diffusion. We hypothesized that convective nutrient transport could extend the loading capacity while also promoting cell viability, rapid glucose equilibration, and the physiological levels of insulin secretion. Here, we showed that convective transport improves nutrient delivery throughout the device and affords a three-dimensional capsule geometry that encapsulates 9.7-fold-more cells than conventional MEDs. Transplantation of a convection-enhanced MED (ceMED) containing insulin-secreting β cells into immunocompetent, hyperglycemic rats demonstrated a rapid, vascular-independent, and glucose-stimulated insulin response, resulting in early amelioration of hyperglycemia, improved glucose tolerance, and reduced fibrosis. Finally, to address potential translational barriers, we outlined future steps necessary to optimize the ceMED design for long-term efficacy and clinical utility.

scholarly journals Sustained Local Delivery of Diclofenac from Three-Dimensional Ultrafine Fibrous Protein Scaffolds with Ultrahigh Drug Loading Capacity

Nanomaterials ◽  
2019 ◽  
Vol 9 (7) ◽  
pp. 918
Author(s):  
S. M. Kamrul Hasan ◽  
Ran Li ◽  
Yichao Wang ◽  
Narendra Reddy ◽  
Wanshuang Liu ◽  
...  
Keyword(s):  
Drug Loading ◽  
Three Dimensional ◽  
Burst Release ◽  
Loading Capacity ◽  
Fibrous Scaffolds ◽  
Fibrous Protein ◽  
Loading Methods ◽  
Functional Components

The three-dimensional (3D) ultrafine fibrous scaffolds loaded with functional components can not only provide support to 3D tissue repair, but also deliver the components in-situ with small dosage and low fusion frequency. However, the conventional loading methods possess drawbacks such as low loading capacity or high burst release. In this research, an ultralow concentration phase separation (ULCPS) technique was developed to form 3D ultrafine gelatin fibers and, meanwhile, load an anti-inflammatory drug, diclofenac, with high capacities for the long-term delivery. The developed scaffolds could achieve a maximum drug loading capacity of 12 wt.% and a highest drug loading efficiency of 84% while maintaining their 3D ultrafine fibrous structure with high specific pore volumes from 227.9 to 237.19 cm3/mg. The initial release at the first hour could be reduced from 34.7% to 42.2%, and a sustained linear release profile was observed with a rate of about 1% per day in the following 30 days. The diclofenac loaded in and released from the ULCPS scaffolds could keep its therapeutic molecular structure. The cell viability has not been affected by the release of drug when the loading was less than 12 wt.%. The results proved the possibility to develop various 3D ultrafine fibrous scaffolds, which can supply functional components in-situ with a long-term.

scholarly journals An Overview of Engineered Hydrogel-Based Biomaterials for Improved β-Cell Survival and Insulin Secretion

2021 ◽  
Vol 9 ◽  
Author(s):  
Azin Ghasemi ◽  
Elham Akbari ◽  
Rana Imani
Keyword(s):  
Insulin Secretion ◽  
Islet Transplantation ◽  
Inflammatory Responses ◽  
Invasive Procedure ◽  
Current Status ◽  
Β Cells ◽  
Comprehensive Overview ◽  
Insulin Secreting Cells

Islet transplantation provides a promising strategy in treating type 1 diabetes as an autoimmune disease, in which damaged β-cells are replaced with new islets in a minimally invasive procedure. Although islet transplantation avoids the complications associated with whole pancreas transplantations, its clinical applications maintain significant drawbacks, including long-term immunosuppression, a lack of compatible donors, and blood-mediated inflammatory responses. Biomaterial-assisted islet transplantation is an emerging technology that embeds desired cells into biomaterials, which are then directly transplanted into the patient, overcoming the aforementioned challenges. Among various biomaterials, hydrogels are the preferred biomaterial of choice in these transplants due to their ECM-like structure and tunable properties. This review aims to present a comprehensive overview of hydrogel-based biomaterials that are engineered for encapsulation of insulin-secreting cells, focusing on new hydrogel design and modification strategies to improve β-cell viability, decrease inflammatory responses, and enhance insulin secretion. We will discuss the current status of clinical studies using therapeutic bioengineering hydrogels in insulin release and prospective approaches.

Effects of Cryopreservation on Cell Viability and Insulin Secretion in a Model Tissue-Engineered Pancreatic Substitute (TEPS)

2005 ◽  
Vol 14 (7) ◽  
pp. 449-456 ◽  
Author(s):  
Neil Mukherjee ◽  
Zhenzhen Chen ◽  
Athanassios Sambanis ◽  
Ying Song
Keyword(s):  
Insulin Secretion ◽  
Cell Viability ◽  
Cell System ◽  
Long Term Storage ◽  
Insulin Secreting Cells ◽  
Insulin Dependent ◽  
Term Storage ◽  
Conventional Freezing ◽  
Pancreatic Substitute

The use of encapsulated insulin-secreting cells constitutes a promising approach towards the treatment of insulin-dependent diabetes. However, long- term storage for off-the-shelf availability still remains an issue, which can be addressed by cryopreservation. This study investigated cryopreservation of a model tissue-engineered pancreatic substitute by two ice-free cryopreservation (vitrification) solutions (designated VS55 and PEG400) in comparison to a conventional freezing protocol. The model substitute consisted of insulin-secreting mouse insulinoma βTC3 cells entrapped in calcium alginate/poly-L-lysine/alginate (APA) beads. Cell viability and static insulin secretion from the thawed cryopreserved groups were characterized and compared against fresh controls. Cell viability tests using alamarBlue® showed that, compared to the fresh groups, the VS55 had the highest viability (p < 0.05), followed by both the PEG400 (p < 0.001) and the frozen groups (p < 0.001). In response to a square wave of glucose, the static insulin secretion data showed that the VS55 and PEG400 groups had similar induction levels against the fresh group, whereas the frozen group had the poorest secretion rate. Cryosubstitution of capsules showed ice formation in the frozen group but no ice in the vitrified groups. Microscopic observations revealed holes and/or tears within beads subjected to freezing, whereas no such abnormalities were detected in the vitrified samples. Overall, vitrification was found to be a promising preservation procedure for this encapsulated cell system.

Aberrant Function and Long-Term Survival of Mouse β Cells Exposed In Vitro to High Glucose Concentrations

1994 ◽  
Vol 3 (5) ◽  
pp. 445-451 ◽  
Author(s):  
Martine Pehuet-Figoni ◽  
Eric Ballot ◽  
Jean-François Bach ◽  
Lucienne Chatenoud
Keyword(s):  
Insulin Secretion ◽  
Glucose Concentration ◽  
Insulin Response ◽  
Basal Medium ◽  
Published Data ◽  
Β Cells ◽  
Experimental Conditions ◽  
Term Survival

In vitro culture of murine Langerhans islets usually ends in islet death after 1-3 wk. Given contradictory published data, we studied the influence of glucose on the function and survival of islets from DBA/2 mice. Islets were cultured on plastic microwells, using 1, 2, or 11 g/l glucose concentrations. Using our routine technique, insulin secretion was evaluated after islet incubation for 15 min in basal medium [(bIS), 1 g/1 glucose], followed by 15 min in stimulating medium [(sIS), 3 g/l glucose, 20 mM/l arginine, 5 mM/l theophylline]. Insulin secretion of islets cultured in 1 g/l glucose remained stable and normal over a period of 2 mo [Day 7: bIS, 6.3 ± 3.1 pU/50 μl; sIS, 16.6 ± 6.8 μU/50 μl. Day 60: bIS, 6.0 ± 4.0 pU/50 μl; sIS, 21.3 ± 10.5 μU/50 μl]. Islet morphology also remained normal. Islets cultured in 2 g/l glucose showed elevated insulin response under basal and stimulating conditions during 2-3 wk, followed by a dramatic drop in insulin secretion [Day 7: bIS, 19.5 ± 5.7 μU/50 μl; sIS, 80.9 ± 10.7 μU/50 μl. Day 60: bIS, 5.4 ± 5.0 μU/50 μl; sIS, 2.7 ± 1.4 μU/50 μl]. Severe morphologic alterations appeared rapidly and islet destruction was nearly complete by 60 days. At 11 g/l glucose, functional and morphological islet alterations were accelerated [Day 7: bIS, 10.3 ± 2.7 μU/50 μl; sIS, 18.8 ± 4.9 μU/50 μl. Day 21: bIS and sIS almost undetectable]. On the basis of the results obtained in our experimental conditions, it may be concluded that the optimal glucose concentration for long-term murine islet cultures is 1 g/l. Based on the results of this study and testing an extracellular matrix, we thereafter cultured islets from DBA/2 mice at the 1 g/l glucose concentration. These islets remained functional for a period of time > 100 days. Abbreviations: bIS: insulin secretion in basal medium; sIS: insulin secretion in stimulating medium; MEM: minimal essential medium.

scholarly journals Targeting Alcohol Septal Ablation in Patients with Obstructive Hypertrophic Cardiomyopathy Candidates for Surgical Myectomy: Added Value of Three-Dimensional Intracoronary Myocardial Contrast Echocardiography

2021 ◽  
Vol 10 (10) ◽  
pp. 2166
Author(s):  
Giovanni La La Canna ◽  
Iside Scarfò ◽  
Irina Arendar ◽  
Antonio Colombo ◽  
Lucia Torracca ◽  
...  
Keyword(s):  
High Risk ◽  
Three Dimensional ◽  
Added Value ◽  
Alcohol Septal Ablation ◽  
High Risk Type ◽  
Life Threatening ◽  
Surgical Myectomy

Background: Myocardial contrast two-dimensional echocardiography (MC-2DE) is widely used to address alcohol septal ablation (ASA) in obstructive hypertrophic cardiomyopathy (HCM). Owing to its limited cut-planes, MC-2DE may inaccurately identify the contrast misplacement associated with an unsuccessful or complicated ASA outcome. Objective: The aim of this study was to assess the added value of myocardial contrast three-dimensional echocardiography (MC-3DE) compared with MC-2DE to identify the appropriate matching between the target septal zone (TSZ) and coronary artery branch for safe and long-term effective ASA in HCM patients. Methods: A consecutive series of 52 symptomatic obstructive HCM patients referred for isolated surgical myectomy (SM) was analyzed with MC-2DE and MC-3DE following injection of echocontrast into one or more septal branches. MC-2DE and MC-3DE patterns were categorized according to complete (Type 1) or incomplete (Type 2) TSZ covering, high-risk (Type 3) exceeding TSZ, or life-threatening outside TSZ distribution (Type 4). Results: MC-2DE per patient analysis showed a Type 1 pattern in 32 patients and Types 2–4 in the remaining 20 patients; subsequent MC-3DE analysis provided a re-phenotyping of MC-2DE findings in 22 of the 52 patients (42%), showing a high-risk Type 2 pattern in 17 of the 32 patients with Type 1, and a new life-threatening Type 4 in three patients with Type 2, respectively. All patients with MC-3DE Type 1 pattern underwent safe and effective ASA with a long-term uneventful follow-up, while the remaining patients underwent SM. Conclusions: Refining high risk or life-threatening contrast misplacement, MC-3DE is more accurate than conventional MC-2DE to target safe and long-term effective septal reduction with ASA in obstructive HCM patients referred for isolated SM.

11β-Hydroxysteroid Dehydrogenase Type 1 Inhibitor Development by Lentiviral Screening Based on Computational Modeling

Pharmacology ◽  
2018 ◽  
Vol 102 (3-4) ◽  
pp. 169-179
Author(s):  
Haifeng Liu ◽  
Lingyu Li ◽  
Chunlei Zhang ◽  
Hongzhi Li ◽  
Jieting Liu ◽  
...  
Keyword(s):  
Viral Vector ◽  
Three Dimensional ◽  
Hydroxysteroid Dehydrogenase ◽  
Gene Bank ◽  
Dimensional Structure ◽  
Drug Candidate ◽  
Lentiviral Transduction ◽  
Stable Manner

In this study, rat and human 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1) have been cloned by lentiviral transduction and expressed by CHO-K1 cells. The results showed that recombinant plasmids contained R11bhsd1 or H11bhsd1 have been constructed, which is consistent with the gene bank respectively. A clone cell was selected with G418 and cultivated to express 11β-HSD1. 11β-HSD1 catalytic activity of rat and human were 99.5 and 98.7%, respectively, determined by scanning radiometer. And the cloned CHO-K1 cells expressed the protein of 11β-HSD1 in a long-term and stable manner, which makes it suitable for screening 11β-HSD1 inhibitor. The three-dimensional structure of 11β-HSD1 was used for studying the interaction between inhibitor and enzyme by the binding poses predicted by AutoDock and LeDock software. The docking results revealed that compound 8 forms 2 hydrogen bonds with the residues of Gly-216 and Ile-218 in 11β-HSD1, that is to say compound 8 maybe a good 11β-HSD1 inhibitor. Moreover, C57BL/6 mice with R11bHsd1 overexpression had a higher body weight, glucose, total cholesterol, and triglyceride levels compared to the mice treated with an empty viral vector. The results might provide a beneficial foundation for selecting inhibitors of 11β-HSD1 or for researching drug candidate mechanisms.

scholarly journals Quercetin Stimulates Insulin Secretion and Reduces the Viability of Rat INS-1 Beta-Cells

2016 ◽  
Vol 39 (1) ◽  
pp. 278-293 ◽  
Author(s):  
Michael Kittl ◽  
Marlena Beyreis ◽  
Munkhtuya Tumurkhuu ◽  
Johannes Fürst ◽  
Katharina Helm ◽  
...  
Keyword(s):  
Insulin Secretion ◽  
Cell Viability ◽  
Beta Cells ◽  
Insulin Release ◽  
Katp Channel ◽  
Annexin V ◽  
Long Term Effects ◽  
Mean Cell Volume ◽  
Channel Inhibition

Background/Aims: Previously we described insulinotropic effects of Leonurus sibiricus L. plant extracts used for diabetes mellitus treatment in Traditional Mongolian Medicine. The flavonoid quercetin and its glycoside rutin, which exert anti-diabetic properties in vivo by interfering with insulin signaling in peripheral target tissues, are constituents of these extracts. This study was performed to better understand short- and long-term effects of quercetin and rutin on beta-cells. Methods: Cell viability, apoptosis, phospho-protein abundance and insulin release were determined using resazurin, annexin-V binding assays, Western blot and ELISA, respectively. Membrane potentials (Vmem), whole-cell Ca2+ (ICa)- and ATP-sensitive K+ (IKATP) currents were measured by patch clamp. Intracellular Ca2+ (Cai) levels were measured by time-lapse imaging using the ratiometric Ca2+ indicator Fura-2. Results: Rutin, quercetin and the phosphoinositide-3-kinase (PI3K) inhibitor LY294002 caused a dose-dependent reduction in cell viability with IC50 values of ∼75 µM, ∼25 µM and ∼3.5 µM, respectively. Quercetin (50 µM) significantly increased the percentage of Annexin-V+ cells within 48 hrs. The mean cell volume (MCV) of quercetin-treated cells was significantly lower. Within 2 hrs, quercetin significantly decreased basal- and insulin-stimulated Akt(T308) phosphorylation and increased Erk1/2 phosphorylation, without affecting P-Akt(S473) abundance. Basal- and glucose-stimulated insulin release were significantly stimulated by quercetin. Quercetin significantly depolarized Vmem by ∼25 mV which was prevented by the KATP-channel opener diazoxide, but not by the L-type ICa inhibitor nifedipine. Quercetin significantly stimulated ICa and caused a 50% inhibition of IKATP. The effects on Vmem, ICa and IKATP rapidly reached peak values and then gradually diminished to control values within ∼1 minute. With a similar time-response quercetin induced an elevation in Cai which was completely abolished in the absence of Ca2+ in the bath solution. Rutin (50 µM) did not significantly alter the percentage of Annexin-V+ cells, MCV, Akt or Erk1/2 phosphorylation, insulin secretion, or the electrophysiological behavior of INS-1 cells. Conclusion: We conclude that quercetin acutely stimulates insulin release, presumably by transient KATP channel inhibition and ICa stimulation. Long term application of quercetin inhibits cell proliferation and induces apoptosis, most likely by inhibition of PI3K/Akt signaling.

scholarly journals A facile, versatile hydrogel bioink for 3D bioprinting benefits long-term subaqueous fidelity, cell viability and proliferation

2021 ◽  
Vol 8 (3) ◽  
Author(s):  
Hongqing Chen ◽  
Fei Fei ◽  
Xinda Li ◽  
Zhenguo Nie ◽  
Dezhi Zhou ◽  
...  
Keyword(s):  
Soft Tissue ◽  
Cell Viability ◽  
Tissue Repair ◽  
Three Dimensional ◽  
Water Retention Capacity ◽  
3D Bioprinting ◽  
Soft Tissue Repair ◽  
Retention Capacity

Abstract Both of the long-term fidelity and cell viability of three-dimensional (3D)-bioprinted constructs are essential to precise soft tissue repair. However, the shrinking/swelling behavior of hydrogels brings about inadequate long-term fidelity of constructs, and bioinks containing excessive polymer are detrimental to cell viability. Here, we obtained a facile hydrogel by introducing 1% aldehyde hyaluronic acid (AHA) and 0.375% N-carboxymethyl chitosan (CMC), two polysaccharides with strong water absorption and water retention capacity, into classic gelatin (GEL, 5%)–alginate (ALG, 1%) ink. This GEL–ALG/CMC/AHA bioink possesses weak temperature dependence due to the Schiff base linkage of CMC/AHA and electrostatic interaction of CMC/ALG. We fabricated integrated constructs through traditional printing at room temperature and in vivo simulation printing at 37°C. The printed cell-laden constructs can maintain subaqueous fidelity for 30 days after being reinforced by 3% calcium chloride for only 20 s. Flow cytometry results showed that the cell viability was 91.38 ± 1.55% on day 29, and the cells in the proliferation plateau at this time still maintained their dynamic renewal with a DNA replication rate of 6.06 ± 1.24%. This work provides a convenient and practical bioink option for 3D bioprinting in precise soft tissue repair.

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